Impedance Matching of Bow-Tie antenna For UWB range

Hi,
I am trying to model a Bow-Tie antenna for UWB range(3.1-10.6GHZ).Bow-tie antenna usually have an impedance of Around 188-200 Ohms at the input port(Mentioned in almost every literature regarding Bow-tie antennas). My problem is i have to design an impedance transformer which converts 50 ohms to 188.5 ohms for the entire UWB range(3.1-10.6GHz). Anyone who has already worked on it or has any useful ideas. Kindly share it here.

Thanks!

No Reply? No one has worked with it before ?

try to use Quater wave transformer.... may b it helps u...... :)